Pots water alarm circuit

  
Are the flowers in pots need watering if the soil surface moist observation alone is sometimes unreliable. For this reason, the production of dry flower instructions which, whe
Pots water alarm circuit - schematic

n the pot of water, the indicator on the flares, watering the flowers to remind people to give. Flower water indicator circuit is shown. The circuit is mainly composed of a field effect transistor VT1, VT2 transistor 555 and a time base circuit, when the soil water, soil resistivity have significantly increased, then M, N great resistance between two points, N-channel junction field effect transistor gate VT1 close to the negative supply voltage, VT1 end. In this case, the base of transistor VT2 through resistor Rz, R3 get the drift, VT2 conduction. VT2 emitter potential rises 555 time base circuit. Since the time base circuit connected to an ultra-low frequency multivibrator, the oscillation frequency of about 1Hz. When the base was a little electricity to work, the light-emitting diodes as the frequency of the low frequency oscillation signal twinkling glow red, to remind people should be given a potted plant watering. When the basin is not water, soil resistivity is very small. Equivalent to M, N have a small resistance between the gate so VT1 near-contact to close the gate voltage ov, conduction between the drain and source of the poles. When VT1 conduction, the drain potential drop, so that VT2 deadline, which the emitter bit is also down to ground potential, time base circuit and therefore stop working, LED tube LED pull no longer shine. When the wine guide VT1, VT2 off, timebase circuit does not work, the entire circuit consumes very little about ImA. Therefore, if the power source on the 5th battery-powered, can also be used for a long time., When used with two wire insulation stripped as two electrodes, inserting them in a pot of soil, the two electrodes separated by a few centimeters can to the. If the circuit is usually not required, as long as a series of miniature switches in the positive power supply circuit can be a negative power consumption is extremely small, very long time without changing the battery. VTJ circuit current rating 0.5N 5mA, pinch-off voltage of about 4V. With 3DJ6E, 3DJ6F or 3DJ6G. VT2 with 3pG6 when available NE555-based circuit.




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